It is generally recognized that cats will not use a dirty litter box. Manual litter boxes require someone to regularly monitor their usage and periodically remove waste from the litter. Regularly removing waste from the litter box also helps to minimize unpleasant odors. Automated or self-cleaning litter boxes attempt to address both of these issues by collecting the waste after each use or, in some cases, on a schedule. Various designs of self-cleaning litter boxes are known in the art. For the most part, existing self-cleaning litter box designs adequately remove waste from the unused litter; however, each existing self-cleaning litter box design generally has one or more undesirable qualities that undermine its effectiveness.